To simplify \( 5^{10} \cdot 5^{5} \) using the Product Rule of Exponents, you add the exponents when multiplying expressions with the same base.
So:
\[ 5^{10} \cdot 5^{5} = 5^{10 + 5} = 5^{15} \]
The correct response is:
5 superscript 15 baseline (515).